Level 75
You can use distinct or groupBy('students.id')
https://laravel.com/docs/8.x/queries#specifying-a-select-clause
But for groupBy('students.id') you will have a problem about strict mode.
1 like
Jun 25, 2021
4
Level 8
Eloquent DB Help
$this->studentsTeacher = DB::table('students')
->join('attendances', 'students.id', '=', 'attendances.student_id')
->where('attendances.teacher_id', $this->teacherId)
->select('students.*')
->get();
I made the error of connecting the student to the teacher through this attendance db, I am now at a problem where I want to just call a list of students for a teacher, but of course, if there are many attendances then the student will get called again, resulting in multiple students being shown on the classroom roster table.
Now, I am not sure how to go about, is there a little work around with the DB query, or should I write another DB which will just have teacherid, studentid, or just add a teacher id on the student table. I am not sure, which would you say be the best work for solution.
Level 1
I assume this is a many to many relationship with a attendances intermediate table. You can create a relationship to Teacher in your your Student model then filter this way
$students = Student::whereHas('teachers', function(Builder $teacher) use ($teacher_id) {
$teacher->where('id', $teacher_id);
})->get();
Be aware this workaround create a "where subquery" instead of a inner join so you won't have to deal with "group by" but it can cause performance issue with very large databases.
1 like
Level 75
whereHas is much slower than join.
1 like
Level 1
Use group or distinct
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